Boiler



Patented June 19, 1928.

UNITED STATES ALEXIS C. MGNULTY, OF RUTHERFORD, NEW JERSEY.

BOILER.

Application filed April 7,

This invention relates to boilers and particularly to the means for heating the feed water supplied to the boiler. It is highly desirable that the maximum portion of the scale forming substances and sediment in the feed water be precipitated prior to the admission of the water to the tubes of the boiler in order that the formation of scale within the boiler proper can be reduced to a minimum. Heretofore attempts have been made to precipitate this scale and sediment in feed water heaters, in which the feed water was heated while passing upwardly in tubes that were surrounded by gases of combustion. The upward movement of the water in the tubes of such preheaters prevented the settling of the precipitated scale forming substances and sediment, and these substances were, therefore, to a large extent carried into the boiler without separation. It is also desirable that a reserve supply of hot feed water be available for admission to the boiler to supply sudden demands.

An object of the invention is to provide an improved boiler and feed water heating device in which feed water will be heated and stored in heated condition for emergency use during sudden loads and supplied as needed to the boiler proper; in which the separation and removal of the scale forming substances and sediment are more effectively and economically accomplished before admission of the feed water to the boiler; in which this preheating may be extended as far as consistent with economies affected thereby, and

which is relatively simple and inexpensive. Other objects and advantages will be apparent from the following description of embodiments of the invention and the novel features will be particularly pointed out in claims.

In the accompanying drawing:

Figure 1 is a sectional elevation of a water tube boiler, setting, and feed water heater constructed in accordance with this invention; and

Figure 2 is a sectional elevation of a duplex boiler and setting to which the invention has been applied,

Referring to Figure 1, an upper horizontal boiler drum or steam chamber 1 is sus pended in a suitable manner, such as by suspension straps 2 to the upper wall of the boiler setting 3. A plurality of water tubes 4 open from the under surface of the upper drum and connect with the upper surface of 1922. Serial No. 550,554.

a lower boiler drum 5, the tubes being separated into two groups by a longitudinal baffie wall 6 projecting from the lower drum upwardly to within a short distance of the upper drum. A bailie wall 7 extends from the upper wall of the setting along the rear water tubes 4 to within a short distance of the lower wall 8 of the setting. A suitable grate 9 is provided adjacent the forward side of the lower drum, upon which the fuel is burned. The combustion gases pass upwardly along and around the water tubes 4 which are disposed forwardly of the bafiie wall 6 and then pass to the rear of the wall 6 through the opening between the wall 6 and the upper water drum. The gases then pass through the conduit between the walls 6 and 7 and through the opening between the lower end of the bafiie wall 7 and the lower wall 8 of the boiler setting. The gases then pass through the conduit 10 to the stack.

A feed water storage drum 11 is suspended in a suitable manner, such as by straps 12 from the upper wall of the setting, the upper surface of the storage drum being below the normal water level in the upper drum 1 of the boiler. A second storage or collecting drum 13 may be disposed below the lower wall 8 of the setting and is connected by nu merous tubes 14 that are disposed in the path of the combustion gases with the under side of the storage tank 11. Tubes 14 have a combined capacity in excess of that nor mally required for feeding the boiler. A conduit 15 connects the upper portion of the lower storage drum 13 with the upper part of the lower drum 5 of the boiler proper, the conduit 15 having a capacity less than the combined capacities of tubes 14. A pipe 16, controlled by a valve 17, leads to the upper part of the storage drum 11 for admitting feed water directly thereto under certain conditions. The feed water passes from the drum 11 downwardly through the tubes 14 at a low velocity and is heated by the flue gases after they have left the boiler proper. A large proportion of the scale forming substances and sediment held in the water is precipitated by the heat and settles slowly downwardly with the descending water in the tubes into the drum 1?). In this drum the velocity is low and the precipitated particles and sediment settle to the bottom of the drum from which they are blown out at suitable intervals by means of a blow-out til) pipe 18 that is controlled by a suitable valve 19.

In order to carry the preheating of the feed water to an extent which will insure a greater precipitation of the scale-forming substances and sediment therefrom. a Il11l11 ber of economizer heating units 20, 21 and may be. utilized. The-e units each comprise an upper storage drum 23 and a lower colr lecting drum 24. the upper and. lower drums being connected by numerous tubes 25. disposed in the path of the combustion gases on their way from the boiler proper to the stack; and running from the lower part of the upper drum to the upper part ot the lower drum. A riser 26 of considerably less capacity than the tubes 25 connects the up per part of each lower drum 24 with the upper storage drum of the unit next. toward the boiler. the riser 26 tor the unit being connected to the storage drum 11 ot the pre heater.

A pipe 2? controlled by a valve 28 is connected to the drum 23 of the unit furthest from the boiler for admittiugthe feed water to the upper drum of the last unit. The water in the upper drum of the last unit will descend slowly through the tubes to the lower collecting drum 2t of that unit, and owing to the heat of the combustion gases passing through the unit and around the tubes 25, the water will be heated and a considerable proportion of the scaleforniing substances and sediment in the water will be precipitated and settle with the descending feed water into the drum 24. The velocity in the lower drum will be less than in the tubes 2.3 and the precipitated solids will settle to the bottom ot the drum from which they may be removed by blowing off at inter ii-ls through a pipe 29 controlled by a valve 30. The water in the lower drum 24 will pass rapidly through the riser 2G to the upper drum 23 of the adjacent unit. (toward the boiler) and will than descend slowly through the tubes 25 of that unit into the lower collecting drum 2% of that unit. A blow-off pipe 29 controlled by a valve 30 is also provided for each lower drum 24 of all of the units for blowing off the precipitated solids at suitable intervals. The water from the lower drum then passes through another riser 26 to the upper storage drum of the next unit towards the boiler. this action proceeding from unit to unit until the water enters the main iced water storage drum 11 of the boiler. Any substances. not removed by the preheating in the feedv Water heaters and econoinizers, and which may enter the lower drum of the boiler and settle therein, may be blown. off at intervals through the blow-ofl pipe 31 leading therefrom and controlled by a valve 32. The upper storage drum 11 of the feed water heater is entirely unconnected with the upper drum of the boiler proper. except through the lower drum 5, so that live steam will not be conducted from the boiler to the storage drum where it would contact with the relatively cool water of the preheater and be coir densed thereby.

In Figure 2 a pair of boiler units and preheaters somewhat similar to that described in: connection with Figure l are arranged upon opposite sides of a. common grate 33, the combustion dividing and pass ing through each boiler unit to the flue conduits 34 and In this embodiment a. single preheater without the economizer units is illustrated but it is to be understood that any number of the economizer units may also be utilized in this embodiment it desired. The tubes 14 of the feed water heater, corresponding to the tubes 14 of Figure 1. instead of being connected to a lower collecting drum 13 of the preheater, are connected directly to the lower drum 5 of the boiler proper, and a depending baffle plate 36 is disposed in this drum to extend from the all of the drum along a line between the tubes 14 and 4- partially across the interior of the drum so as to.prevent too direct a movement of the teed water from the tubes 14 into the boiler tubes without first passing to the int crior of the lower drum. The plate 36 therefore in effect divides the drum 5 into two drums which are connected. The velocity of the teed water entering through the tubes 14 will be reduced in the drum 5" because of its greater capacity and the precipitated solids or sediment will settle to the bottom of the drum from which they may be removed by blowing oil the boiler at suitable iutem'als through a blow-oil pipe 37 that is controlled by a. valve 38. The upper drums 1 til the. units are connected by pipes 359 to a com mon steam transmission pipe 10 that is controlled by a valve ll.

The feed water may be admitted through pipe 16 controlled by a valve T to the storage drum ll from which it will descend slowly through the tubes it to the drum 5. The combustion gases leaving the proper pass around the tubes lat so to heat the descending water. The scale forming substances and sediment are precipitated and settle slowly with the slowly de-- scending water in thetubes ll into the lower drum 5 of the bolier and then settle to the bottom of the lower drum. The lower drum is blownofl' at suitable intervals through the blow-off pipe 37 to remove this collection of precipitated solids.

It will be observed that since the precipitation occurs almost entirely while the teed water is slowly descending in the heating tubes, the settling and removal of the precipitated solids and sediment will be facilitated. The storage drum ll acts as a reseroir of hot feed water for supplying the boiler during sudden loads. Any number of the economizer units may be added to the main feed water preheater.

It will be obvious that various changes in the details and arrangement of parts in the embodiments herein described and illustratcd for the purpose of explaining the nature of the invention, may be made by those skilled in the art within the principle and scope of the invention.

I claim:

1. A feed water heating device for boilers comprising a storage drum disposed entirely below the normal water level in the boiler and unconnected with the steam chamber thereof, a collecting drum below the storage drum. tubes around which the combustion gases pass in leaving the boiler connected between the storage and collecting drums, a connection between the upper part of the collecting drum and the boiler below the water lavel, the capacity of the connection being materially le s than the combined capacities of the tubes whereby the velocity.

of the water in the tubes will be materially less than that in the connection, a blow-oti' pipe connected to the lower part of the collecting drum, and means tor supplying feed water to said storage drum.

2. A feed water heating device for boilcrs comprising a storage drum disposed entirely below the normal water level in the boiler and unconnected with the steam chamber thereof, tubes descending from said storage drum in the path of the combustion gases and connected to said boiler below the normal water level therein, an economize! unit disposed in the path of the combustion gases and comprising an upper drum, a low er drum and a plurality of tubes connects ing the upper drum with the upper part of the lower drum, riser means connecting the upper part. of the lower drum with the storage drum. the capacity of the riser means being materially less than the combined capacities ot' the plurality of tubes between the upper and lower drums whereby the downward flow is relatively slow and the upward flow is relatively rapid. and means fo admitting feed water to the up per drum.

3. A feed water heating device for boil ers comprising a storage drum unconnected with the steam chamber of the boiler, means connecting the storage drum to the boiler below the normal Water line including descending tubes disposed in the path of the combustion gases leaving the boiler, the aggregate capacity of the tubes being considerably greater than that required for supplying the needs of the boiler whereby the heating of the feed water will largely occur while slowly descending in the tubes.

4. A feed water heating device for boilers comprising a storage drum, connected to said boiler below the normal water level, an economizer unit disposed in the path of the combustion gases and comprising an upper drum, a lower drum and a plurality of tubes connecting the upper drum with the upper part of the lower drum, riser means connecting the upper part of the lower drum with the storage drum, the capacity of the riser means being materially less than the combined capacities of the plurality of tubes between the upper and lower drums whereby the downward flow is relatively slow and the upward flow is relatively rapid, means for removing the collected sediment from the lower drum, and .means for admitting feed water to the upper drum.

5. A feed water heating device for boilers comprising a storage drum, connected to said boiler, an economizer unit disposed in the path of the combustion gases and comprising an upper drum, a lower drum and a plurality of tubes connecting the upper drum with the upper part of the lower drum, riser means connecting the upper part of the lower drum with the storage drum, the capacity of the riser means being materially less than the combined capacities of the plurality of tubes between the upper and lower drums whereby the downward flow is relatively slow and the upward flow is relatively rapid, means for removing the collected sediment from the lower drum, and means for admitting feed water to the upper drum.

6. A feed water heating device for boilers comprising a storage drum unconnected with the steam chamber of the boiler, a collecting drum below the storage drum, tubes around which the combustion gases pass in leaving the boiler connected between the storage and collecting drums, a connection between the upper part of the collecting drum and the boiler below the water level, the capacity of the connection being materially less than the combined capacities of the tubes whereby the velocity of the water in the tubes will be materially less than that in the connection, a blow-off pipe connected to the lower part of the collecting drum, and means for supplying feed water to said drum.

In witness whereof, I hereunto subscribe my signature.

ALEXIS C. McNULT Y. 

